René Nyffenegger's collection of things on the web
René Nyffenegger on Oracle - Most wanted - Feedback -

Advanced Queuing [Oracle]

Oracle 9i embeds Advanced Queuing, which is an integrated, persistent, reliable, secure, scalable, and transactional message-queuing framework.
For example, the deferred transaction queue of Oracle's replication is implementeed with Advanced queuing.
Go here for an example.